On the angels, they are best in groups of 5-6, and must be added at the same time to avoid trouble. You can read why in our profile, click on the shaded name Pterophyllum scalare. They also will go after small fish, though not barbs, but the rasbora might be a target when the angels are mature at 6 inches with 8+ inch fin spans. Severum are much the same, at 8 inches a threat to any smaller fish.

African rift lake cichlids are not compatible with other fish as "community" due to their significant difference in water parameters and behaviours. They deserve their own space.

"Large centerpiece" fish are not easy, and usually impossible, unless the tank is very large, thinking of several hundred gallons. One must remember that while certain fish species may be found in the same habitat naturally, they usually occupy very different areas and seldom come into contact. Or if they do, there is space for the smaller to escape easily, and the larger seldom bother them. In the aquarium, no matter how large in a home, it is still a relatively confined space for any fish, and they have no escape from other fish.

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian.[unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]

In my 55gl my ph is like 7.4 and I have 15 neon's + some other random small fish. I also have it heavily planted with a herd of Cherry shrimp that keeps growing. Neon's are cool and easy to take care of since I have found fry so they must be happy :)